$(document).ready(function () {
    $('.nav_content_item').click(function () {
        $('.nav_content_item').find('span').removeClass('nav_span_select').removeClass('nav_span_unselect');
        $(this).find('span').addClass('nav_span_select');
        $('.nav_content_item').not(this).find('span').addClass('nav_span_unselect');
        let index = $(this).data("index");
        switch (index) {
            case 0:
                var url = "../index.html";
                window.open(url, '_blank');
                break;
            case 1:
                var url = "../html/survey.html";
                window.open(url, '_blank');
                break;
            case 2:
                var url = "../html/analyse.html";
                window.open(url, '_blank');
                break;
            case 3:
                var url = "../html/brand.html";
                window.open(url, '_blank');
                break;
            case 4:
                var url = "../html/knowledge.html";
                window.open(url, '_blank');
                break;
            case 5:
                var url = "../html/policy.html";
                window.open(url, '_blank');
                break;
            case 6:
                var url = "../html/forum.html";
                window.open(url, '_blank');
                break;
        }

    });
    $('.menu_item').click(function () {
        $('.menu_item').removeClass('menu_item_select');
        $(this).addClass('menu_item_select');
        $('.menu_item').not(this).removeClass('menu_item_select');
    });
});
